Thyroid hormone status affects expression of daily torpor and gene transcription in Djungarian hamsters (Phodopus sungorus)
Thyroid hormone status affects expression of daily torpor and gene transcription in Djungarian hamsters (Phodopus sungorus)
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DOI：
10.1016/j.yhbeh.2015.09.006
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发表时间：
2015-09-01
影响因子：
3.5
通讯作者：
Herwig, Annika
中科院分区：
文献类型：
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作者：
Bank, Jonathan H. H.;Kemmling, Julia;Herwig, Annika
甲状腺激素(TH)在调节新陈代谢的季节性和急性变化方面起着关键作用。丛林仓鼠通过行为和生理的多种变化来适应冬季，包括自发的日常麻木、低代谢和低温状态。我们研究了全身注射TH和消融对适应短光周期的金黄地鼠的麻木行为的影响。T4或T3诱发甲亢，他巴唑(MMI)和高氯酸钠饮水诱发甲状腺功能减退。T3处理增加了水份、摄食量和体质量，而MMI则相反。连续记录体温显示，低T_3血清浓度增加了昏迷发生率，降低了T-b和持续时间，而高T_3血清浓度抑制了昏迷表现。用定量聚合酶链式反应技术分析下丘脑、棕色脂肪组织和骨骼肌中脱碘酶(DIO)和解偶联蛋白(UCP)的基因表达。参与体温调节的Dio2和UCPs的表达表明了对治疗的组织特异性反应。昏迷本身降低了dio2的表达，与治疗或组织无关，这表明在昏迷期间细胞内T3浓度较低。昏迷期间UCP1和UCP3的下调可能是抑制BAT产热的因素之一。下丘脑神经肽Y、前黑素皮质素和生长抑素的基因表达与摄食行为和能量平衡有关，不受治疗的影响。综上所述，我们的数据表明甲状腺激素对麻木有很强的影响，提示外周组织中较低的细胞内T3浓度促进了麻木。(C)2015 Elsevier Inc.保留所有权利。
Thyroid hormones (TH) play a key role in regulation of seasonal as well as acute changes in metabolism. Djungarian hamsters (Phodopus sungorus) adapt to winter by multiple changes in behaviour and physiology including spontaneous daily torpor, a state of hypometabolism and hypothermia. We investigated effects of systemic TH administration and ablation on the torpor behaviour in Djungarian hamsters adapted to short photoperiod. Hyperthyroidism was induced by giving T4 or T3 and hypothyroidism by giving methimazole (MMI) and sodium perchlorate via drinking water. T3 treatment increased water, food intake and body mass, whereas MMI had the opposite effect. Continuous recording of body temperature revealed that low T3 serum concentrations increased torpor incidence, lowered T-b and duration, whereas high T3 serum concentrations inhibited torpor expression. Gene expression of deiodinases (dio) and uncoupling proteins (ucp) were analysed by qPCR in hypothalamus, brown adipose tissue (BAT) and skeletal muscle. Expression of dio2, the enzyme generating T3 by deiodination of T4, and ucps, involved in thermoregulation, indicated a tissue specific response to treatment. Torpor per se decreased dio2 expression irrespective of treatment or tissue, suggesting low intracellular T3 concentrations during torpor. Down regulation of ucp1 and ucp3 during torpor might be a factor for the inhibition of BAT thermogenesis. Hypothalamic gene expression of neuropeptide Y, propopiomelanocortin and somatostatin, involved in feeding behaviour and energy balance, were not affected by treatment. Taken together our data indicate a strong effect of thyroid hormones on torpor, suggesting that lowered intracellular T3 concentrations in peripheral tissues promote torpor. (C) 2015 Elsevier Inc. All rights reserved.